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perf tools: Don't read build-ids from non-regular files

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Simplify the build ID reading code by removing the non-blocking option.
Having to pass the correct option to this function was fragile and a
mistake would result in a hang, see the linked fix. Furthermore,
compressed files are always opened blocking anyway, ignoring the
non-blocking option.

We also don't expect to read build IDs from non-regular files. The only
hits to this function that are non-regular are devices that won't be elf
files with build IDs, for example "/dev/dri/renderD129".

Now instead of opening these as non-blocking and failing to read, we
skip them. Even if something like a pipe or character device did have a
build ID, I don't think it would have worked because you need to call
read() in a loop, check for -EAGAIN and handle timeouts to make
non-blocking reads work.

Link: https://lore.kernel.org/linux-perf-users/20251022-james-perf-fix-dso-block-v1-1-c4faab150546@linaro.org/
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
James Clark
2025-11-24 10:59:08 +00:00
committed by Namhyung Kim
parent c957328772
commit 834ebb5678
15 changed files with 43 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tools/perf/bench/inject-buildid.c
View File

@@ -85,7 +85,7 @@ static int add_dso(const char *fpath, const struct stat *sb __maybe_unused,
if (typeflag == FTW_D || typeflag == FTW_SL)
return 0;
if (filename__read_build_id(fpath, &bid, /*block=*/true) < 0)
if (filename__read_build_id(fpath, &bid) < 0)
return 0;
dso->name = realpath(fpath, NULL);

8
tools/perf/builtin-buildid-cache.c
View File

@@ -180,7 +180,7 @@ static int build_id_cache__add_file(const char *filename, struct nsinfo *nsi)
struct nscookie nsc;
nsinfo__mountns_enter(nsi, &nsc);
err = filename__read_build_id(filename, &bid, /*block=*/true);
err = filename__read_build_id(filename, &bid);
nsinfo__mountns_exit(&nsc);
if (err < 0) {
pr_debug("Couldn't read a build-id in %s\n", filename);
@@ -204,7 +204,7 @@ static int build_id_cache__remove_file(const char *filename, struct nsinfo *nsi)
int err;
nsinfo__mountns_enter(nsi, &nsc);
err = filename__read_build_id(filename, &bid, /*block=*/true);
err = filename__read_build_id(filename, &bid);
nsinfo__mountns_exit(&nsc);
if (err < 0) {
pr_debug("Couldn't read a build-id in %s\n", filename);
@@ -280,7 +280,7 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
if (!dso__build_id_filename(dso, filename, sizeof(filename), false))
return true;
if (filename__read_build_id(filename, &bid, /*block=*/true) == -1) {
if (filename__read_build_id(filename, &bid) == -1) {
if (errno == ENOENT)
return false;
@@ -309,7 +309,7 @@ static int build_id_cache__update_file(const char *filename, struct nsinfo *nsi)
int err;
nsinfo__mountns_enter(nsi, &nsc);
err = filename__read_build_id(filename, &bid, /*block=*/true);
err = filename__read_build_id(filename, &bid);
nsinfo__mountns_exit(&nsc);
if (err < 0) {
pr_debug("Couldn't read a build-id in %s\n", filename);

4
tools/perf/builtin-inject.c
View File

@@ -668,12 +668,12 @@ static int dso__read_build_id(struct dso *dso)
mutex_lock(dso__lock(dso));
nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
if (filename__read_build_id(dso__long_name(dso), &bid, /*block=*/true) > 0)
if (filename__read_build_id(dso__long_name(dso), &bid) > 0)
dso__set_build_id(dso, &bid);
else if (dso__nsinfo(dso)) {
char *new_name = dso__filename_with_chroot(dso, dso__long_name(dso));
if (new_name && filename__read_build_id(new_name, &bid, /*block=*/true) > 0)
if (new_name && filename__read_build_id(new_name, &bid) > 0)
dso__set_build_id(dso, &bid);
free(new_name);
}

4
tools/perf/tests/pe-file-parsing.c
View File

@@ -37,7 +37,7 @@ static int run_dir(const char *d)
size_t idx;
scnprintf(filename, PATH_MAX, "%s/pe-file.exe", d);
ret = filename__read_build_id(filename, &bid, /*block=*/true);
ret = filename__read_build_id(filename, &bid);
TEST_ASSERT_VAL("Failed to read build_id",
ret == sizeof(expect_build_id));
TEST_ASSERT_VAL("Wrong build_id", !memcmp(bid.data, expect_build_id,
@@ -49,7 +49,7 @@ static int run_dir(const char *d)
!strcmp(debuglink, expect_debuglink));
scnprintf(debugfile, PATH_MAX, "%s/%s", d, debuglink);
ret = filename__read_build_id(debugfile, &bid, /*block=*/true);
ret = filename__read_build_id(debugfile, &bid);
TEST_ASSERT_VAL("Failed to read debug file build_id",
ret == sizeof(expect_build_id));
TEST_ASSERT_VAL("Wrong build_id", !memcmp(bid.data, expect_build_id,

2
tools/perf/tests/sdt.c
View File

@@ -31,7 +31,7 @@ static int build_id_cache__add_file(const char *filename)
struct build_id bid = { .size = 0, };
int err;
err = filename__read_build_id(filename, &bid, /*block=*/true);
err = filename__read_build_id(filename, &bid);
if (err < 0) {
pr_debug("Failed to read build id of %s\n", filename);
return err;

4
tools/perf/util/build-id.c
View File

@@ -122,7 +122,7 @@ int filename__snprintf_build_id(const char *pathname, char *sbuild_id, size_t sb
struct build_id bid = { .size = 0, };
int ret;
ret = filename__read_build_id(pathname, &bid, /*block=*/true);
ret = filename__read_build_id(pathname, &bid);
if (ret < 0)
return ret;
@@ -848,7 +848,7 @@ static int filename__read_build_id_ns(const char *filename,
int ret;
nsinfo__mountns_enter(nsi, &nsc);
ret = filename__read_build_id(filename, bid, /*block=*/true);
ret = filename__read_build_id(filename, bid);
nsinfo__mountns_exit(&nsc);
return ret;

2
tools/perf/util/debuginfo.c
View File

@@ -115,7 +115,7 @@ struct debuginfo *debuginfo__new(const char *path)
* incase the path isn't for a regular file.
*/
assert(!dso__has_build_id(dso));
if (filename__read_build_id(path, &bid, /*block=*/false) > 0)
if (filename__read_build_id(path, &bid) > 0)
dso__set_build_id(dso, &bid);
for (type = distro_dwarf_types;

4
tools/perf/util/dsos.c
View File

@@ -81,13 +81,13 @@ static int dsos__read_build_ids_cb(struct dso *dso, void *data)
return 0;
}
nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
if (filename__read_build_id(dso__long_name(dso), &bid, /*block=*/true) > 0) {
if (filename__read_build_id(dso__long_name(dso), &bid) > 0) {
dso__set_build_id(dso, &bid);
args->have_build_id = true;
} else if (errno == ENOENT && dso__nsinfo(dso)) {
char *new_name = dso__filename_with_chroot(dso, dso__long_name(dso));
if (new_name && filename__read_build_id(new_name, &bid, /*block=*/true) > 0) {
if (new_name && filename__read_build_id(new_name, &bid) > 0) {
dso__set_build_id(dso, &bid);
args->have_build_id = true;
}

9
tools/perf/util/libbfd.c
View File

@@ -383,13 +383,18 @@ out_close:
return err;
}
int libbfd__read_build_id(const char *filename, struct build_id *bid, bool block)
int libbfd__read_build_id(const char *filename, struct build_id *bid)
{
size_t size = sizeof(bid->data);
int err = -1, fd;
bfd *abfd;
fd = open(filename, block ? O_RDONLY : (O_RDONLY | O_NONBLOCK));
if (!filename)
return -EFAULT;
if (!is_regular_file(filename))
return -EWOULDBLOCK;
fd = open(filename, O_RDONLY);
if (fd < 0)
return -1;

5
tools/perf/util/libbfd.h
View File

@@ -25,7 +25,7 @@ void dso__free_a2l_libbfd(struct dso *dso);
int symbol__disassemble_libbfd(const char *filename, struct symbol *sym,
struct annotate_args *args);
int libbfd__read_build_id(const char *filename, struct build_id *bid, bool block);
int libbfd__read_build_id(const char *filename, struct build_id *bid);
int libbfd_filename__read_debuglink(const char *filename, char *debuglink, size_t size);
@@ -59,8 +59,7 @@ static inline int symbol__disassemble_libbfd(const char *filename __always_unuse
}
static inline int libbfd__read_build_id(const char *filename __always_unused,
struct build_id *bid __always_unused,
bool block __always_unused)
struct build_id *bid __always_unused)
{
return -1;
}

13
tools/perf/util/symbol-elf.c
View File

@@ -860,20 +860,20 @@ out:
return err;
}
static int read_build_id(const char *filename, struct build_id *bid, bool block)
static int read_build_id(const char *filename, struct build_id *bid)
{
size_t size = sizeof(bid->data);
int fd, err;
Elf *elf;
err = libbfd__read_build_id(filename, bid, block);
err = libbfd__read_build_id(filename, bid);
if (err >= 0)
goto out;
if (size < BUILD_ID_SIZE)
goto out;
fd = open(filename, block ? O_RDONLY : (O_RDONLY | O_NONBLOCK));
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
@@ -894,7 +894,7 @@ out:
return err;
}
int filename__read_build_id(const char *filename, struct build_id *bid, bool block)
int filename__read_build_id(const char *filename, struct build_id *bid)
{
struct kmod_path m = { .name = NULL, };
char path[PATH_MAX];
@@ -902,6 +902,8 @@ int filename__read_build_id(const char *filename, struct build_id *bid, bool blo
if (!filename)
return -EFAULT;
if (!is_regular_file(filename))
return -EWOULDBLOCK;
err = kmod_path__parse(&m, filename);
if (err)
@@ -918,10 +920,9 @@ int filename__read_build_id(const char *filename, struct build_id *bid, bool blo
}
close(fd);
filename = path;
block = true;
}
err = read_build_id(filename, bid, block);
err = read_build_id(filename, bid);
if (m.comp)
unlink(filename);

11
tools/perf/util/symbol-minimal.c
View File

@@ -85,7 +85,7 @@ int filename__read_debuglink(const char *filename __maybe_unused,
/*
* Just try PT_NOTE header otherwise fails
*/
int filename__read_build_id(const char *filename, struct build_id *bid, bool block)
int filename__read_build_id(const char *filename, struct build_id *bid)
{
int fd, ret = -1;
bool need_swap = false, elf32;
@@ -102,7 +102,12 @@ int filename__read_build_id(const char *filename, struct build_id *bid, bool blo
void *phdr, *buf = NULL;
ssize_t phdr_size, ehdr_size, buf_size = 0;
fd = open(filename, block ? O_RDONLY : (O_RDONLY | O_NONBLOCK));
if (!filename)
return -EFAULT;
if (!is_regular_file(filename))
return -EWOULDBLOCK;
fd = open(filename, O_RDONLY);
if (fd < 0)
return -1;
@@ -323,7 +328,7 @@ int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
if (ret >= 0)
RC_CHK_ACCESS(dso)->is_64_bit = ret;
if (filename__read_build_id(ss->name, &bid, /*block=*/true) > 0)
if (filename__read_build_id(ss->name, &bid) > 0)
dso__set_build_id(dso, &bid);
return 0;
}

5
tools/perf/util/symbol.c
View File

@@ -1743,14 +1743,13 @@ int dso__load(struct dso *dso, struct map *map)
/*
* Read the build id if possible. This is required for
* DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work. Don't block in case path
* isn't for a regular file.
* DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work.
*/
if (!dso__has_build_id(dso)) {
struct build_id bid = { .size = 0, };
__symbol__join_symfs(name, PATH_MAX, dso__long_name(dso));
if (filename__read_build_id(name, &bid, /*block=*/false) > 0)
if (filename__read_build_id(name, &bid) > 0)
dso__set_build_id(dso, &bid);
}

2
tools/perf/util/symbol.h
View File

@@ -140,7 +140,7 @@ struct symbol *dso__next_symbol(struct symbol *sym);
enum dso_type dso__type_fd(int fd);
int filename__read_build_id(const char *filename, struct build_id *id, bool block);
int filename__read_build_id(const char *filename, struct build_id *id);
int sysfs__read_build_id(const char *filename, struct build_id *bid);
int modules__parse(const char *filename, void *arg,
int (*process_module)(void *arg, const char *name,

2
tools/perf/util/synthetic-events.c
View File

@@ -401,7 +401,7 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
nsi = nsinfo__new(event->pid);
nsinfo__mountns_enter(nsi, &nc);
rc = filename__read_build_id(event->filename, &bid, /*block=*/false) > 0 ? 0 : -1;
rc = filename__read_build_id(event->filename, &bid) > 0 ? 0 : -1;
nsinfo__mountns_exit(&nc);
nsinfo__put(nsi);